Autosave form – Inactivity Error on Idle

I’m using module.

When user is idle for few minutes, it gives below error message.

A server error occurred during autosaving the current page. As a result autosave is disabled. To activate it please revisit the page and continue the editing from the last autosaved state of the current page.

File: autosave_form/js/autosave_form.js